/*
 * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package java.io;

import org.mini.fs.InnerRandomAccessFile;

/**
 * Instances of this class support both reading and writing to a random access
 * file. A random access file behaves like a large array of bytes stored in the
 * file system. There is a kind of cursor, or index into the implied array,
 * called the <em>file pointer</em>; input operations read bytes starting at the
 * file pointer and advance the file pointer past the bytes read. If the random
 * access file is created in read/write mode, then output operations are also
 * available; output operations write bytes starting at the file pointer and
 * advance the file pointer past the bytes written. Output operations that write
 * past the current end of the implied array cause the array to be extended. The
 * file pointer can be read by the <code>getFilePointer</code> method and set by
 * the <code>seek</code> method.
 * <p>
 * It is generally true of all the reading routines in this class that if
 * end-of-file is reached before the desired number of bytes has been read, an
 * <code>EOFException</code> (which is a kind of <code>IOException</code>) is
 * thrown. If any byte cannot be read for any reason other than end-of-file, an
 * <code>IOException</code> other than <code>EOFException</code> is thrown. In
 * particular, an <code>IOException</code> may be thrown if the stream has been
 * closed.
 *
 * @author unascribed
 * @version 1.78, 05/13/04
 * @since JDK1.0
 */
public class RandomAccessFile implements DataOutput, DataInput {

    private FileDescriptor fd;
    private InnerRandomAccessFile iraf = null;
    private boolean rw;

    private static final int O_RDONLY = 1;
    private static final int O_RDWR = 2;
    private static final int O_SYNC = 4;
    private static final int O_DSYNC = 8;

    /**
     * Creates a random access file stream to read from, and optionally to write
     * to, a file with the specified name. A new {@link FileDescriptor} object
     * is created to represent the connection to the file.
     *
     * <p>
     * The <tt>mode</tt> argument specifies the access mode with which the file
     * is to be opened. The permitted values and their meanings are as specified
     * for the <a
     * href="#mode"><tt>RandomAccessFile(File,String)</tt></a> constructor.
     *
     * <p>
     * If there is a security manager, its <code>checkRead</code> method is
     * called with the <code>name</code> argument as its argument to see if read
     * access to the file is allowed. If the mode allows writing, the security
     * manager's <code>checkWrite</code> method is also called with the
     * <code>name</code> argument as its argument to see if write access to the
     * file is allowed.
     *
     * @param name the system-dependent filename
     * @param mode the access <a href="#mode">mode</a>
     * @exception IllegalArgumentException if the mode argument is not equal to
     * one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or
     * <tt>"rwd"</tt>
     * @exception IOException if the mode is <tt>"r"</tt> but the given string
     * does not denote an existing regular file, or if the mode begins with
     * <tt>"rw"</tt> but the given string does not denote an existing, writable
     * regular file and a new regular file of that name cannot be created, or if
     * some other error occurs while opening or creating the file
     * @exception SecurityException if a security manager exists and its
     * <code>checkRead</code> method denies read access to the file or the mode
     * is "rw" and the security manager's <code>checkWrite</code> method denies
     * write access to the file
     * @see java.lang.SecurityException
     * @see java.lang.SecurityManager#checkRead(java.lang.String)
     * @see java.lang.SecurityManager#checkWrite(java.lang.String)
     * @revised 1.4
     * @spec JSR-51
     */
    public RandomAccessFile(String name, String mode)
            throws IOException {
        this(name != null ? new File(name) : null, mode);
    }

    /**
     * Creates a random access file stream to read from, and optionally to write
     * to, the file specified by the {@link File} argument. A new {@link
     * FileDescriptor} object is created to represent this file connection.
     *
     * <a name="mode"><p>
     * The <tt>mode</tt> argument specifies the access mode in which the file is
     * to be opened. The permitted values and their meanings are:
     *
     * <blockquote><table summary="Access mode permitted values and meanings">
     * <tr><th><p align="left">Value</p></th><th><p align="left">Meaning</p></th></tr>
     * <tr><td valign="top"><tt>"r"</tt></td>
     * <td> Open for reading only. Invoking any of the <tt>write</tt>
     * methods of the resulting object will cause an {@link
     *     java.io.IOException} to be thrown. </td></tr>
     * <tr><td valign="top"><tt>"rw"</tt></td>
     * <td> Open for reading and writing. If the file does not already exist
     * then an attempt will be made to create it. </td></tr>
     * <tr><td valign="top"><tt>"rws"</tt></td>
     * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also
     * require that every update to the file's content or metadata be written
     * synchronously to the underlying storage device.  </td></tr>
     * <tr><td valign="top"><tt>"rwd"&nbsp;&nbsp;</tt></td>
     * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also
     * require that every update to the file's content be written synchronously
     * to the underlying storage device. </td></tr>
     * </table></blockquote>
     *
     * The <tt>"rws"</tt> and <tt>"rwd"</tt> modes work much like the {@link
     * java.nio.channels.FileChannel#force(boolean) force(boolean)} method of
     * the {@link java.nio.channels.FileChannel} class, passing arguments of
     * <tt>true</tt> and <tt>false</tt>, respectively, except that they always
     * apply to every I/O operation and are therefore often more efficient. If
     * the file resides on a local storage device then when an invocation of a
     * method of this class returns it is guaranteed that all changes made to
     * the file by that invocation will have been written to that device. This
     * is useful for ensuring that critical information is not lost in the event
     * of a system crash. If the file does not reside on a local device then no
     * such guarantee is made.
     *
     * <p>
     * The <tt>"rwd"</tt> mode can be used to reduce the number of I/O
     * operations performed. Using <tt>"rwd"</tt> only requires updates to the
     * file's content to be written to storage; using <tt>"rws"</tt> requires
     * updates to both the file's content and its metadata to be written, which
     * generally requires at least one more low-level I/O operation.
     *
     * <p>
     * If there is a security manager, its <code>checkRead</code> method is
     * called with the pathname of the <code>file</code> argument as its
     * argument to see if read access to the file is allowed. If the mode allows
     * writing, the security manager's <code>checkWrite</code> method is also
     * called with the path argument to see if write access to the file is
     * allowed.
     *
     * @param file the file object
     * @param mode the access mode, as described
     * <a href="#mode">above</a>
     * @exception IllegalArgumentException if the mode argument is not equal to
     * one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or
     * <tt>"rwd"</tt>
     * @exception IOException if the mode is <tt>"r"</tt> but the given file
     * object does not denote an existing regular file, or if the mode begins
     * with <tt>"rw"</tt> but the given file object does not denote an existing,
     * writable regular file and a new regular file of that name cannot be
     * created, or if some other error occurs while opening or creating the file
     * @exception SecurityException if a security manager exists and its
     * <code>checkRead</code> method denies read access to the file or the mode
     * is "rw" and the security manager's <code>checkWrite</code> method denies
     * write access to the file
     * @see java.lang.SecurityManager#checkRead(java.lang.String)
     * @see java.lang.SecurityManager#checkWrite(java.lang.String)
     * @see java.nio.channels.FileChannel#force(boolean)
     * @revised 1.4
     * @spec JSR-51
     */
    public RandomAccessFile(File file, String mode)
            throws IOException {
        String name = (file != null ? file.getPath() : null);
        int imode = -1;
        if (mode.equals("r")) {
            imode = O_RDONLY;
        } else if (mode.startsWith("rw")) {
            imode = O_RDWR;
            rw = true;
            if (mode.length() > 2) {
                if (mode.equals("rws")) {
                    imode |= O_SYNC;
                } else if (mode.equals("rwd")) {
                    imode |= O_DSYNC;
                } else {
                    imode = -1;
                }
            }
        }
        if (imode < 0) {
            throw new IllegalArgumentException("Illegal mode \"" + mode
                    + "\" must be one of "
                    + "\"r\", \"rw\", \"rws\","
                    + " or \"rwd\"");
        }
        if (name == null) {
            throw new NullPointerException();
        }
        fd = new FileDescriptor();
        //open(name, imode);
        iraf = new InnerRandomAccessFile(name, mode);
    }

    /**
     * Returns the opaque file descriptor object associated with this stream.
     * </p>
     *
     * @return the file descriptor object associated with this stream.
     * @exception IOException if an I/O error occurs.
     * @see java.io.FileDescriptor
     */
    public final FileDescriptor getFD() throws IOException {
        if (fd != null) {
            return fd;
        }
        throw new IOException();
    }

    /**
     * Opens a file and returns the file descriptor. The file is opened in
     * read-write mode if the O_RDWR bit in <code>mode</code> is true, else the
     * file is opened as read-only. If the <code>name</code> refers to a
     * directory, an IOException is thrown.
     *
     * @param name the name of the file
     * @param mode the mode flags, a combination of the O_ constants defined
     * above
     */
//    private native void open(String name, int mode)
//            throws IOException;
//
    // 'Read' primitives
    /**
     * Reads a byte of data from this file. The byte is returned as an integer
     * in the range 0 to 255 (<code>0x00-0x0ff</code>). This method blocks if no
     * input is yet available.
     * <p>
     * Although <code>RandomAccessFile</code> is not a subclass of
     * <code>InputStream</code>, this method behaves in exactly the same way as
     * the {@link InputStream#read()} method of <code>InputStream</code>.
     *
     * @return the next byte of data, or <code>-1</code> if the end of the file
     * has been reached.
     * @exception IOException if an I/O error occurs. Not thrown if end-of-file
     * has been reached.
     */
    public int read() throws IOException {
        return iraf.read();
    }

    /**
     * Reads a sub array as a sequence of bytes.
     *
     * @param b the buffer into which the data is read.
     * @param off the start offset of the data.
     * @param len the number of bytes to read.
     * @exception IOException If an I/O error has occurred.
     */
    private int readBytes(byte b[], int off, int len) throws IOException{
        return iraf.read(b, off, len);
    }

    /**
     * Reads up to <code>len</code> bytes of data from this file into an array
     * of bytes. This method blocks until at least one byte of input is
     * available.
     * <p>
     * Although <code>RandomAccessFile</code> is not a subclass of
     * <code>InputStream</code>, this method behaves in exactly the same way as
     * the {@link InputStream#read(byte[], int, int)} method of
     * <code>InputStream</code>.
     *
     * @param b the buffer into which the data is read.
     * @param off the start offset of the data.
     * @param len the maximum number of bytes read.
     * @return the total number of bytes read into the buffer, or
     * <code>-1</code> if there is no more data because the end of the file has
     * been reached.
     * @exception IOException if an I/O error occurs.
     */
    public int read(byte b[], int off, int len) throws IOException {
        return readBytes(b, off, len);
    }

    /**
     * Reads up to <code>b.length</code> bytes of data from this file into an
     * array of bytes. This method blocks until at least one byte of input is
     * available.
     * <p>
     * Although <code>RandomAccessFile</code> is not a subclass of
     * <code>InputStream</code>, this method behaves in exactly the same way as
     * the {@link InputStream#read(byte[])} method of <code>InputStream</code>.
     *
     * @param b the buffer into which the data is read.
     * @return the total number of bytes read into the buffer, or
     * <code>-1</code> if there is no more data because the end of this file has
     * been reached.
     * @exception IOException if an I/O error occurs.
     */
    public int read(byte b[]) throws IOException {
        return readBytes(b, 0, b.length);
    }

    /**
     * Reads <code>b.length</code> bytes from this file into the byte array,
     * starting at the current file pointer. This method reads repeatedly from
     * the file until the requested number of bytes are read. This method blocks
     * until the requested number of bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @param b the buffer into which the data is read.
     * @exception EOFException if this file reaches the end before reading all
     * the bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final void readFully(byte b[]) throws IOException {
        readFully(b, 0, b.length);
    }

    /**
     * Reads exactly <code>len</code> bytes from this file into the byte array,
     * starting at the current file pointer. This method reads repeatedly from
     * the file until the requested number of bytes are read. This method blocks
     * until the requested number of bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @param b the buffer into which the data is read.
     * @param off the start offset of the data.
     * @param len the number of bytes to read.
     * @exception EOFException if this file reaches the end before reading all
     * the bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final void readFully(byte b[], int off, int len) throws IOException {
        int n = 0;
        do {
            int count = this.read(b, off + n, len - n);
            if (count < 0) {
                throw new EOFException();
            }
            n += count;
        } while (n < len);
    }

    /**
     * Attempts to skip over <code>n</code> bytes of input discarding the
     * skipped bytes.
     * <p>
     *
     * This method may skip over some smaller number of bytes, possibly zero.
     * This may result from any of a number of conditions; reaching end of file
     * before <code>n</code> bytes have been skipped is only one possibility.
     * This method never throws an <code>EOFException</code>. The actual number
     * of bytes skipped is returned. If <code>n</code> is negative, no bytes are
     * skipped.
     *
     * @param n the number of bytes to be skipped.
     * @return the actual number of bytes skipped.
     * @exception IOException if an I/O error occurs.
     */
    public int skipBytes(int n) throws IOException {
        long pos;
        long len;
        long newpos;

        if (n <= 0) {
            return 0;
        }
        pos = getFilePointer();
        len = length();
        newpos = pos + n;
        if (newpos > len) {
            newpos = len;
        }
        seek(newpos);

        /* return the actual number of bytes skipped */
        return (int) (newpos - pos);
    }

    // 'Write' primitives
    /**
     * Writes the specified byte to this file. The write starts at the current
     * file pointer.
     *
     * @param b the <code>byte</code> to be written.
     * @exception IOException if an I/O error occurs.
     */
    public void write(int b) throws IOException {
        iraf.write(b);
    }

    /**
     * Writes a sub array as a sequence of bytes.
     *
     * @param b the data to be written
     *
     * @param off the start offset in the data
     * @param len the number of bytes that are written
     * @exception IOException If an I/O error has occurred.
     */
    private void writeBytes(byte b[], int off, int len) throws IOException {
        int wrote = 0;
        int ret = 0;
        while ((ret = iraf.write(b, wrote + off, len - wrote)) < len) {

            if (ret < 0) {
                throw new IOException("write file error.");
            }
            wrote += ret;
//            System.out.println("wrote=" + wrote + ", len=" + len);
        }
    }

    /**
     * Writes <code>b.length</code> bytes from the specified byte array to this
     * file, starting at the current file pointer.
     *
     * @param b the data.
     * @exception IOException if an I/O error occurs.
     */
    public void write(byte b[]) throws IOException {
        writeBytes(b, 0, b.length);
    }

    /**
     * Writes <code>len</code> bytes from the specified byte array starting at
     * offset <code>off</code> to this file.
     *
     * @param b the data.
     * @param off the start offset in the data.
     * @param len the number of bytes to write.
     * @exception IOException if an I/O error occurs.
     */
    public void write(byte b[], int off, int len) throws IOException {
        writeBytes(b, off, len);
    }

    // 'Random access' stuff
    /**
     * Returns the current offset in this file.
     *
     * @return the offset from the beginning of the file, in bytes, at which the
     * next read or write occurs.
     * @exception IOException if an I/O error occurs.
     */
    public long getFilePointer() throws IOException {
        return iraf.getFilePointer();
    }

    /**
     * Sets the file-pointer offset, measured from the beginning of this file,
     * at which the next read or write occurs. The offset may be set beyond the
     * end of the file. Setting the offset beyond the end of the file does not
     * change the file length. The file length will change only by writing after
     * the offset has been set beyond the end of the file.
     *
     * @param pos the offset position, measured in bytes from the beginning of
     * the file, at which to set the file pointer.
     * @exception IOException if <code>pos</code> is less than <code>0</code> or
     * if an I/O error occurs.
     */
    public void seek(long pos) throws IOException {
        iraf.seek(pos);
    }

    /**
     * Returns the length of this file.
     *
     * @return the length of this file, measured in bytes.
     * @exception IOException if an I/O error occurs.
     */
    public long length() throws IOException {
        return iraf.length();
    }

    /**
     * Sets the length of this file.
     *
     * <p>
     * If the present length of the file as returned by the <code>length</code>
     * method is greater than the <code>newLength</code> argument then the file
     * will be truncated. In this case, if the file offset as returned by the
     * <code>getFilePointer</code> method is greater than <code>newLength</code>
     * then after this method returns the offset will be equal to
     * <code>newLength</code>.
     *
     * <p>
     * If the present length of the file as returned by the <code>length</code>
     * method is smaller than the <code>newLength</code> argument then the file
     * will be extended. In this case, the contents of the extended portion of
     * the file are not defined.
     *
     * @param newLength The desired length of the file
     * @exception IOException If an I/O error occurs
     * @since 1.2
     */
    public void setLength(long newLength) throws IOException {
        iraf.setLength(newLength);
    }

    /**
     * Closes this random access file stream and releases any system resources
     * associated with the stream. A closed random access file cannot perform
     * input or output operations and cannot be reopened.
     *
     * <p>
     * If this file has an associated channel then the channel is closed as
     * well.
     *
     * @exception IOException if an I/O error occurs.
     *
     * @revised 1.4
     * @spec JSR-51
     */
    public void close() throws IOException {
        iraf.close();
    }

    //
    //  Some "reading/writing Java data types" methods stolen from
    //  DataInputStream and DataOutputStream.
    //
    /**
     * Reads a <code>boolean</code> from this file. This method reads a single
     * byte from the file, starting at the current file pointer. A value of
     * <code>0</code> represents <code>false</code>. Any other value represents
     * <code>true</code>. This method blocks until the byte is read, the end of
     * the stream is detected, or an exception is thrown.
     *
     * @return the <code>boolean</code> value read.
     * @exception EOFException if this file has reached the end.
     * @exception IOException if an I/O error occurs.
     */
    public final boolean readBoolean() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return (ch != 0);
    }

    /**
     * Reads a signed eight-bit value from this file. This method reads a byte
     * from the file, starting from the current file pointer. If the byte read
     * is <code>b</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b&nbsp;&lt;=&nbsp;255</code>, then the result is:
     * <blockquote><pre>
     *     (byte)(b)
     * </pre></blockquote>
     * <p>
     * This method blocks until the byte is read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return the next byte of this file as a signed eight-bit
     * <code>byte</code>.
     * @exception EOFException if this file has reached the end.
     * @exception IOException if an I/O error occurs.
     */
    public final byte readByte() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return (byte) (ch);
    }

    /**
     * Reads an unsigned eight-bit number from this file. This method reads a
     * byte from this file, starting at the current file pointer, and returns
     * that byte.
     * <p>
     * This method blocks until the byte is read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return the next byte of this file, interpreted as an unsigned eight-bit
     * number.
     * @exception EOFException if this file has reached the end.
     * @exception IOException if an I/O error occurs.
     */
    public final int readUnsignedByte() throws IOException {
        int ch = this.read();
        if (ch < 0) {
            throw new EOFException();
        }
        return ch;
    }

    /**
     * Reads a signed 16-bit number from this file. The method reads two bytes
     * from this file, starting at the current file pointer. If the two bytes
     * read, in order, are <code>b1</code> and <code>b2</code>, where each of
     * the two values is between <code>0</code> and <code>255</code>, inclusive,
     * then the result is equal to:
     * <blockquote><pre>
     *     (short)((b1 &lt;&lt; 8) | b2)
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return the next two bytes of this file, interpreted as a signed 16-bit
     * number.
     * @exception EOFException if this file reaches the end before reading two
     * bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final short readShort() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0) {
            throw new EOFException();
        }
        return (short) ((ch1 << 8) + (ch2 << 0));
    }

    /**
     * Reads an unsigned 16-bit number from this file. This method reads two
     * bytes from the file, starting at the current file pointer. If the bytes
     * read, in order, are <code>b1</code> and <code>b2</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1, b2&nbsp;&lt;=&nbsp;255</code>, then the
     * result is equal to:
     * <blockquote><pre>
     *     (b1 &lt;&lt; 8) | b2
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return the next two bytes of this file, interpreted as an unsigned
     * 16-bit integer.
     * @exception EOFException if this file reaches the end before reading two
     * bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final int readUnsignedShort() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0) {
            throw new EOFException();
        }
        return (ch1 << 8) + (ch2 << 0);
    }

    /**
     * Reads a Unicode character from this file. This method reads two bytes
     * from the file, starting at the current file pointer. If the bytes read,
     * in order, are <code>b1</code> and <code>b2</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1,&nbsp;b2&nbsp;&lt;=&nbsp;255</code>, then the
     * result is equal to:
     * <blockquote><pre>
     *     (char)((b1 &lt;&lt; 8) | b2)
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return the next two bytes of this file as a Unicode character.
     * @exception EOFException if this file reaches the end before reading two
     * bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final char readChar() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0) {
            throw new EOFException();
        }
        return (char) ((ch1 << 8) + (ch2 << 0));
    }

    /**
     * Reads a signed 32-bit integer from this file. This method reads 4 bytes
     * from the file, starting at the current file pointer. If the bytes read,
     * in order, are <code>b1</code>, <code>b2</code>, <code>b3</code>, and
     * <code>b4</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1, b2, b3, b4&nbsp;&lt;=&nbsp;255</code>, then
     * the result is equal to:
     * <blockquote><pre>
     *     (b1 &lt;&lt; 24) | (b2 &lt;&lt; 16) + (b3 &lt;&lt; 8) + b4
     * </pre></blockquote>
     * <p>
     * This method blocks until the four bytes are read, the end of the stream
     * is detected, or an exception is thrown.
     *
     * @return the next four bytes of this file, interpreted as an
     * <code>int</code>.
     * @exception EOFException if this file reaches the end before reading four
     * bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final int readInt() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        int ch3 = this.read();
        int ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0) {
            throw new EOFException();
        }
        return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
    }

    /**
     * Reads a signed 64-bit integer from this file. This method reads eight
     * bytes from the file, starting at the current file pointer. If the bytes
     * read, in order, are <code>b1</code>, <code>b2</code>, <code>b3</code>,
     * <code>b4</code>, <code>b5</code>, <code>b6</code>, <code>b7</code>, and
     * <code>b8,</code> where:
     * <blockquote><pre>
     *     0 &lt;= b1, b2, b3, b4, b5, b6, b7, b8 &lt;=255,
     * </pre></blockquote>
     * <p>
     * then the result is equal to:
     * <p>
     * <blockquote><pre>
     *     ((long)b1 &lt;&lt; 56) + ((long)b2 &lt;&lt; 48)
     *     + ((long)b3 &lt;&lt; 40) + ((long)b4 &lt;&lt; 32)
     *     + ((long)b5 &lt;&lt; 24) + ((long)b6 &lt;&lt; 16)
     *     + ((long)b7 &lt;&lt; 8) + b8
     * </pre></blockquote>
     * <p>
     * This method blocks until the eight bytes are read, the end of the stream
     * is detected, or an exception is thrown.
     *
     * @return the next eight bytes of this file, interpreted as a
     * <code>long</code>.
     * @exception EOFException if this file reaches the end before reading eight
     * bytes.
     * @exception IOException if an I/O error occurs.
     */
    public final long readLong() throws IOException {
        return ((long) (readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
    }

    /**
     * Reads a <code>float</code> from this file. This method reads an
     * <code>int</code> value, starting at the current file pointer, as if by
     * the <code>readInt</code> method and then converts that <code>int</code>
     * to a <code>float</code> using the <code>intBitsToFloat</code> method in
     * class <code>Float</code>.
     * <p>
     * This method blocks until the four bytes are read, the end of the stream
     * is detected, or an exception is thrown.
     *
     * @return the next four bytes of this file, interpreted as a
     * <code>float</code>.
     * @exception EOFException if this file reaches the end before reading four
     * bytes.
     * @exception IOException if an I/O error occurs.
     * @see java.io.RandomAccessFile#readInt()
     * @see java.lang.Float#intBitsToFloat(int)
     */
    public final float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }

    /**
     * Reads a <code>double</code> from this file. This method reads a
     * <code>long</code> value, starting at the current file pointer, as if by
     * the <code>readLong</code> method and then converts that <code>long</code>
     * to a <code>double</code> using the <code>longBitsToDouble</code> method
     * in class <code>Double</code>.
     * <p>
     * This method blocks until the eight bytes are read, the end of the stream
     * is detected, or an exception is thrown.
     *
     * @return the next eight bytes of this file, interpreted as a
     * <code>double</code>.
     * @exception EOFException if this file reaches the end before reading eight
     * bytes.
     * @exception IOException if an I/O error occurs.
     * @see java.io.RandomAccessFile#readLong()
     * @see java.lang.Double#longBitsToDouble(long)
     */
    public final double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }

    /**
     * Reads the next line of text from this file. This method successively
     * reads bytes from the file, starting at the current file pointer, until it
     * reaches a line terminator or the end of the file. Each byte is converted
     * into a character by taking the byte's value for the lower eight bits of
     * the character and setting the high eight bits of the character to zero.
     * This method does not, therefore, support the full Unicode character set.
     *
     * <p>
     * A line of text is terminated by a carriage-return character
     * (<code>'&#92;r'</code>), a newline character (<code>'&#92;n'</code>), a
     * carriage-return character immediately followed by a newline character, or
     * the end of the file. Line-terminating characters are discarded and are
     * not included as part of the string returned.
     *
     * <p>
     * This method blocks until a newline character is read, a carriage return
     * and the byte following it are read (to see if it is a newline), the end
     * of the file is reached, or an exception is thrown.
     *
     * @return the next line of text from this file, or null if end of file is
     * encountered before even one byte is read.
     * @exception IOException if an I/O error occurs.
     */
    public final String readLine() throws IOException {
        StringBuffer input = new StringBuffer();
        int c = -1;
        boolean eol = false;

        while (!eol) {
            switch (c = read()) {
                case -1:
                case '\n':
                    eol = true;
                    break;
                case '\r':
                    eol = true;
                    long cur = getFilePointer();
                    if ((read()) != '\n') {
                        seek(cur);
                    }
                    break;
                default:
                    input.append((char) c);
                    break;
            }
        }

        if ((c == -1) && (input.length() == 0)) {
            return null;
        }
        return input.toString();
    }

    /**
     * Reads in a string from this file. The string has been encoded using a
     * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
     * format.
     * <p>
     * The first two bytes are read, starting from the current file pointer, as
     * if by <code>readUnsignedShort</code>. This value gives the number of
     * following bytes that are in the encoded string, not the length of the
     * resulting string. The following bytes are then interpreted as bytes
     * encoding characters in the modified UTF-8 format and are converted into
     * characters.
     * <p>
     * This method blocks until all the bytes are read, the end of the stream is
     * detected, or an exception is thrown.
     *
     * @return a Unicode string.
     * @exception EOFException if this file reaches the end before reading all
     * the bytes.
     * @exception IOException if an I/O error occurs.
     * @exception UTFDataFormatException if the bytes do not represent valid
     * modified UTF-8 encoding of a Unicode string.
     * @see java.io.RandomAccessFile#readUnsignedShort()
     */
    public final String readUTF() throws IOException {
        return DataInputStream.readUTF(this);
    }

    /**
     * Writes a <code>boolean</code> to the file as a one-byte value. The value
     * <code>true</code> is written out as the value <code>(byte)1</code>; the
     * value <code>false</code> is written out as the value
     * <code>(byte)0</code>. The write starts at the current position of the
     * file pointer.
     *
     * @param v a <code>boolean</code> value to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeBoolean(boolean v) throws IOException {
        write(v ? 1 : 0);
        //written++;
    }

    /**
     * Writes a <code>byte</code> to the file as a one-byte value. The write
     * starts at the current position of the file pointer.
     *
     * @param v a <code>byte</code> value to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeByte(int v) throws IOException {
        write(v);
        //written++;
    }

    /**
     * Writes a <code>short</code> to the file as two bytes, high byte first.
     * The write starts at the current position of the file pointer.
     *
     * @param v a <code>short</code> to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeShort(int v) throws IOException {
        write((v >>> 8) & 0xFF);
        write((v >>> 0) & 0xFF);
        //written += 2;
    }

    /**
     * Writes a <code>char</code> to the file as a two-byte value, high byte
     * first. The write starts at the current position of the file pointer.
     *
     * @param v a <code>char</code> value to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeChar(int v) throws IOException {
        write((v >>> 8) & 0xFF);
        write((v >>> 0) & 0xFF);
        //written += 2;
    }

    /**
     * Writes an <code>int</code> to the file as four bytes, high byte first.
     * The write starts at the current position of the file pointer.
     *
     * @param v an <code>int</code> to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeInt(int v) throws IOException {
        write((v >>> 24) & 0xFF);
        write((v >>> 16) & 0xFF);
        write((v >>> 8) & 0xFF);
        write((v >>> 0) & 0xFF);
        //written += 4;
    }

    /**
     * Writes a <code>long</code> to the file as eight bytes, high byte first.
     * The write starts at the current position of the file pointer.
     *
     * @param v a <code>long</code> to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeLong(long v) throws IOException {
        write((int) (v >>> 56) & 0xFF);
        write((int) (v >>> 48) & 0xFF);
        write((int) (v >>> 40) & 0xFF);
        write((int) (v >>> 32) & 0xFF);
        write((int) (v >>> 24) & 0xFF);
        write((int) (v >>> 16) & 0xFF);
        write((int) (v >>> 8) & 0xFF);
        write((int) (v >>> 0) & 0xFF);
        //written += 8;
    }

    /**
     * Converts the float argument to an <code>int</code> using the
     * <code>floatToIntBits</code> method in class <code>Float</code>, and then
     * writes that <code>int</code> value to the file as a four-byte quantity,
     * high byte first. The write starts at the current position of the file
     * pointer.
     *
     * @param v a <code>float</code> value to be written.
     * @exception IOException if an I/O error occurs.
     * @see java.lang.Float#floatToIntBits(float)
     */
    public final void writeFloat(float v) throws IOException {
        writeInt(Float.floatToIntBits(v));
    }

    /**
     * Converts the double argument to a <code>long</code> using the
     * <code>doubleToLongBits</code> method in class <code>Double</code>, and
     * then writes that <code>long</code> value to the file as an eight-byte
     * quantity, high byte first. The write starts at the current position of
     * the file pointer.
     *
     * @param v a <code>double</code> value to be written.
     * @exception IOException if an I/O error occurs.
     * @see java.lang.Double#doubleToLongBits(double)
     */
    public final void writeDouble(double v) throws IOException {
        writeLong(Double.doubleToLongBits(v));
    }

    /**
     * Writes the string to the file as a sequence of bytes. Each character in
     * the string is written out, in sequence, by discarding its high eight
     * bits. The write starts at the current position of the file pointer.
     *
     * @param s a string of bytes to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeBytes(String s) throws IOException {
        int len = s.length();
        byte[] b
                = s.getBytes();
        writeBytes(b, 0, len);
    }

    /**
     * Writes a string to the file as a sequence of characters. Each character
     * is written to the data output stream as if by the <code>writeChar</code>
     * method. The write starts at the current position of the file pointer.
     *
     * @param s a <code>String</code> value to be written.
     * @exception IOException if an I/O error occurs.
     * @see java.io.RandomAccessFile#writeChar(int)
     */
    public final void writeChars(String s) throws IOException {
        int clen = s.length();
        int blen = 2 * clen;
        byte[] b = new byte[blen];
        char[] c = new char[clen];
        s.getChars(0, clen, c, 0);
        for (int i = 0, j = 0; i < clen; i++) {
            b[j++] = (byte) (c[i] >>> 8);
            b[j++] = (byte) (c[i] >>> 0);
        }
        writeBytes(b, 0, blen);
    }

    /**
     * Writes a string to the file using
     * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
     * encoding in a machine-independent manner.
     * <p>
     * First, two bytes are written to the file, starting at the current file
     * pointer, as if by the <code>writeShort</code> method giving the number of
     * bytes to follow. This value is the number of bytes actually written out,
     * not the length of the string. Following the length, each character of the
     * string is output, in sequence, using the modified UTF-8 encoding for each
     * character.
     *
     * @param str a string to be written.
     * @exception IOException if an I/O error occurs.
     */
    public final void writeUTF(String str) throws IOException {
        DataOutputStream.writeUTF(str, this);
    }

}
